High power ferroelectric RF phase shifter

Abstract

The high power ferroelectric RF phase shifter contains a ferroelectric material in a microstrip line section. Between the ferroelectric phase shifter and the input, there is a ferroelectric matching transformer. Between the ferroelectric phase shifter and the output, there is a quarter wave ferroelectric matching transformer. A bias field is connected across the top and bottom surfaces of the ferroelectric material. When a bias field is applied across the ferroelectric material, the permittivity is reduced and as such the velocity of propagation is increased. This causes an increase in the effective electrical length of the phase shifter. Increasing the bias voltage increases the phase shift. The ferroelectric RF phase shifter may be constructed of a ferroelectric liquid crystal (FLC). The ferroelectric material is operated above its Curie temperature.

What is claimed is: 
     
       1. A high Tc superconducting ferroelectric phase shifter having an input, an output, a top, a bottom, a ground plane, an operating frequency, having Curie temperatures, being operated at a high Tc superconducting temperature, with an electric field dependent permittivity and comprising of: a first microstrip line section disposed on a first ferroelectric material characterized by said permittivity;   a second microstrip line section disposed on a second ferroelectric material, characterized by said permittivity, being quarter wavelength long at the operating frequency of said phase shifter, for matching the impedance of an input of said phase shifter to the impedance of said first microstrip line and being a part thereof;   a third microstrip line section disposed on said second ferroelectric material, characterized by said permittivity, being quarter wavelength long, at the operating frequency of said phase shifter for matching the impedance of an output of said phase shifter to the impedance of said first microstrip, line and being a part thereof;   said second and third microstrip lines having respective widths being greater than a width of said first microstrip line;   said ground plane comprised of a conductive deposition on said bottom side of said phase shifter;   a film of a single crystal high Tc superconductor material continuously defining said first, second and third microstrip lines;   means, connected to the microstrip lines, for applying a variable bias electric field to change said permittivity of said ferroelectric materials of said phase shifter; and   said phase shifter being operated at a constant high Tc superconducting temperature slightly above the Curie temperatures of the ferroelectric materials.   
     
     
       2. A ferroelectric phase shifter of claim 1 wherein said first and second ferroelectric materials being ferroelectric liquid crystal materials.   
     
     
       3. A ferroelectric phase shifter of claim 1 wherein said phase shifter being a MMIC. 
     
     
       4. A monolithic high Tc superconducting ferroelectric phase shifter having an input, an output, a top, a bottom, a ground plane, an operating frequency, being operated at a high Tc superconducting temperature, having a Curie temperature, with an electric field dependent permittivity and comprising of: a first microstrip line section disposed on a first film of a ferroelectric material characterized by said permittivity;   a second microstrip line section disposed on a second film of a ferroelectric material, characterized by said permittivity, having a transformer being quarter wavelength long, at the operating frequency of the phase shifter for matching the impedance of an input of the phase shifter to the first microstrip line;   a third microstrip line section disposed on a third film of a ferroelectric material having a transformer being quarter wavelength long, at the operating frequency of the phase shifter for matching the impedance of said first microstrip line of the phase shifter to an output of the phase shifter;   said second and third microstrip lines having respective widths being smaller than a width of said first microstrip line;   said first, second and third microstrip lines being disposed and connected together on said respective ferroelectric films;   a film of a single crystal high Tc superconductor material continuously defining said first, second and third microstrip lines;   means, connected to said microstrip lines, for applying an electric field to the phase shifter to change the permittivity of said respective ferroelectric films and thus to obtain a differential phase shift; and   said phase shifter being operated at a constant high Tc superconducting temperature slightly above the Curie temperature of the ferroelectric material.   
     
     
       5. A ferroelectric phase shifter of claim 4 wherein said phase shifter being a monolithic microwave integrated circuit (MMIC).   
     
     
       6. A ferroelectric phase shifter of claim 4 wherein the single crystal high TC superconductor being YBCO. 
     
     
       7. A high Tc superconducting monolithic ferroelectric phase shifter having an input, an output, a top, a bottom, a ground plane, an operating frequency, having edge coupled filters, having Curie temperatures, being operated at a high Tc superconducting temperature, with an electric field dependent permittivity and comprising of; a first microstrip line section disposed on a first film of a first ferroelectric material characterized by said permittivity;   a second microstrip line section disposed on a second film of a second ferroelectric material having a transformer being quarter wavelength long, at the operating frequency of the phase shifter, for matching the impedance of an input of the phase shifter to the first microstrip line;   a third microstrip line section disposed on a third film of a second ferroelectric material having a transformer being quarter wavelength long, at the operating frequency of the phase shifter, for matching the impedance of said first microstrip line of the phase shifter to an output of the phase shifter;   said second and third microstrip lines having respective widths being greater than a width of said first microstrip line;   said first, second and third microstrip lines being disposed and connected together on said respective ferroelectric films;   a plurality of edge coupled filter respectively disposed at said input and at said output to isolate the bias voltage of said phase shifter from the input and the output of the phase shifter and comprising of:   a fourth microstrip line disposed on a film of a first dielectric material being quarter wavelength long at the operating frequency of said phase shifter, and being connected, with a first appropriate length of an uncoupled line, to said input quarter wavelength transformer;   a fifth microstrip line disposed on a film of a first dielectric material, edge coupled to said fourth microstrip line and being quarter wavelength long, at the operating frequency of said phase shifter, and being connected, with a first appropriate length of an uncoupled microstrip line, to the input;   a sixth microstrip line on a film of a first dielectric material being quarter wavelength long, at the operating frequency of said phase shifter, and being connected, with a first appropriate length of an uncoupled line, to said output quarter wavelength transformer;   a seventh microstrip line on a film of a first dielectric material, edge coupled to said sixth microstrip line and being quarter wavelength long, at the operating frequency of said phase shifter, and being connected, with a first appropriate length of an uncoupled microstrip line, to the output;   a film of a single crystal high Tc superconductor material continuously defining said first, second, third, fourth and sixth microstrip lines;   a film of a single crystal high Tc superconductor material continuously defining said fifth microstrip line;   a film of a single crystal high Tc superconductor material continuously defining said seventh microstrip line;   means, connected to said microstrip lines, for applying an electric field to the phase shifter to change the permittivity of said respective ferroelectric films and thus to obtain a differential phase shift; and   said phase shifter being operated at a constant high Tc superconducting temperature slightly above the Curie temperatures of the ferroelectric materials.   
     
     
       8. A ferroelectric phase shifter of claim 7 wherein the phase shifter is a monolithic microwave integrated circuit (MMIC).